Monoazo black dye and process of making same.



UNITED STATES PATENT OFFICE.

FRIEDRICH KREOKE, OF BIEBRIOI I, GERMANY, ASSIGNOR TO KALLE & 00.,

OF SAME PLACE.

MIONOAHZO BLACK DYE. ANDJPROCESS 0F MAKl NG SAME.

SPECIFICATION forming part of Letters Patent N 0. 664,955, dated d'anuary 1, 1901.

Application filed November 6, 1900.

To all whom it may concern: '1

Be it known that I, FRIEDRICH KREOKE, a subject of the King of Prussia, Emperor of Germany,residingatBiebrich,Germany,have invented certain new and useful Improve-' ments in the Manufacture of a Black Mordant Dyestufi, of which the following is a specification. 'My present invention relates to the-manufacture of a new monoazo dyestufi by combining diazotized picramic acid with 1.6 dioxynaphthaleue-3-sulfonic acid. I illustrate my process by the following example: 22.1

kilos ofthe sodium salt of picramic acid are dissolved in five hundred liters of hot water, reprecipitated by addition of thirty kilos hydrochloric acidof thirty per cent. and transformed after cooling with ice to 10 centigrade into the diazo compound by addition of 6.9 kilos sodium nitrite dissolved in fift'y liters of water. Into the diazo liquid I run a neutral solution of twentyseven kilos s0- dium, 1.6 dioxynaphthalene-3-sulfonate, and subsequently I add twenty kilos crystallized sodium acetate. After the combination is finished the liquid is rendered" alkaline by adding thirty kilos soda-ash. The dyestuff is then salted out, pressed, and dried.

The new dyestuff is a dark-colored powder showing metallic luster. It is easily soluble in water withreddish-violet color, in concentrated sulfuric acid with violet color, and very Serial No. 36,54ii. (No specimens.)

difficultly soluble in alcohol. It dyes a deepnew monoazo dyestufi by combining diazo- Q tized picramic acid with 1.6 dioxynaphthalene- 3.-sulfoni c acid.

2. As a new product the dyestufi obtained by combination of diazoti zedpicramic acid with 1.6 dio'xynaphthalene-6-sulf0nic acid, be-

ing a dark-colored powder with metallic luster easily soluble in water with reddish-violet color, in concentrated sulfuric acid with violetcolor, very diflicultly soluble in alcohol,

dyeing on wool from an acid-bath a deep violet, which is changed-into a deep black of excelchromium salts.

In testimony whereof .I have signed my name to this specification in the presence of two subscribing witnesses.

. FRIEDRICH KREOKE. Witnesses:

JEAN GRUND, CARL GRu'N lent fastuess by a subsequent treatment with 

